As semiconductor industry has been developed significantly, the generation of information communication having a new communication paradigm, in which multimedia functions of compact electric/electronic appliances, such as notebook computers, cellular phones, DMB phones or portable communication systems based on bidirectional communication are generalized instead of simple information reception, has been come.
Since graphite-based secondary batteries appeared in the market, the energy density of a battery has undergone rapid development and reached two times or higher of the energy density of the early time of its development. However, there has been a continuous need for a high-capacity battery. Particularly, there is an imminent need for developing an anode material having excellent high-rate charge/discharge characteristics. Because the capacity of a battery depends on the charge/discharge characteristics of an anode material, improvement of an anode active material has been given many attentions in many battery developers.
Many studies have been conducted to date about using a graphite-based carbonaceous material as an anode material for lithium ion secondary batteries. However, in the case of a graphite-based carbonaceous material, it still needs improvement in terms of a charge/discharge rate so that it is applied to vehicles, such as hybrid cars, although it may be provided with high energy density per unit volume. Meanwhile, a lithium ion secondary battery using an amorphous carbonaceous material has a large irreversible capacity and low energy density per unit volume. Therefore, many attempts have been made to develop a porous carbonaceous material having a high energy density and efficiency.
Meanwhile, porous materials are classified into microporous materials (2 nm or less), mesoporous materials (2-50 nm) and macroporous materials (50 nm or more), depending on pore diameters. In addition, such porous materials may be applied to various industrial fields, including catalysts, separation systems, low-dielectric constant materials, hydrogen storage materials and photonics crystals, by controlling pore sizes and distributions and surface areas. Thus, such porous materials have been given many attentions in the art.
Porous materials include inorganic materials, metals, polymers and carbon. Among those, carbon has excellent chemical, mechanical and thermal stability, is economical, is applicable to various uses, and has excellent surface characteristics, ion conductivity and electron conductivity. Therefore, active studies have been conducted about porous carbonaceous materials having excellent lithium ion storability even in high-rate charge/discharge cycles and realizing a high energy density per unit volume. However, there is a problem in that it is difficult to provide a carbonaceous material showing excellent porous characteristics through well-developed pores while still maintaining a high surface area.